TW202413449A - Resin composition, fluorine-based resin film, fluorine-based resin metal-coated laminate, and printed wiring board - Google Patents

Abstract

The present invention provides a resin composition capable of improving the filling property of an inorganic filler and ensuring the adhesion of a fluorine-based resin on a substrate material such as a metal substrate by laminating the fluorine-based resin on the substrate material, a fluorine-based resin film obtained by using the resin composition, and a fluorine-based resin-coated metal laminate. The present invention is a resin composition comprising a resin component (A) containing a fluorine-based resin and an inorganic filler (B), wherein the ratio of (A) to the total of (A) and (B) is 20 mass% to 50 mass%, and the ratio of (B) is 50 mass% to 80 mass%, the ratio of the fluorine-based resin in (A) is 50 mass% or more, the volume ratio of particles of 3 μm or less in (B) is 10% or more and less than 30%, the D50 indicating 50% of the cumulative distribution on a volume basis is 8 μm or more and 15 μm or less, and the D90 is 30 μm or less, and the present invention is a fluorine-based resin film obtained using the resin composition, and a fluorine-based resin-coated metal laminate.

Description

Resin composition, fluorine-based resin film using the same, and fluorine-based resin-coated metal laminate

The present invention relates to a resin composition having a resin component including a fluorine-based resin and an inorganic filler, a fluorine-based resin film using the resin composition, and a fluorine-based resin-coated metal laminate. Specifically, the present invention relates to a resin composition including a fluorine-based resin having a small relative dielectric constant and a small dielectric loss tangent as a resin component, and is suitable for applications such as substrate materials intended to be used in high-frequency regions, a fluorine-based resin film using the resin composition, and further a fluorine-based resin-coated metal laminate.

Fluorine-based resins are used in various materials such as automotive parts and semiconductors due to their excellent heat resistance, chemical resistance, and wear resistance. In addition, fluorine-based resins have a molecular structure similar to tetrafluoroethylene (-C ₂ F ₄ -), with a short distance between carbon and fluorine, and have electrical properties such as low dielectric properties and low dielectric loss, so they are also used in insulation materials, coaxial cables, printed circuit boards, etc.

Among them, recently, fifth-generation mobile communication (5th Generation Mobile Communication Technology, 5G) services have begun to use millimeter wave bands. Since these will cause very large transmission loss and insertion loss, fluorine-based resins are particularly attracting attention as materials suitable for high-frequency characteristics.

Fluorine-based resins have high flexibility in their polymer chains. Therefore, when used in resin layers of substrate materials, inorganic fillers are added to improve mechanical strength, or resin compositions containing inorganic fillers are used to impart heat dissipation or adjust the thermal expansion coefficient when laminated with a metal substrate.

However, if the amount of inorganic filler added is too large, the dispersibility with the fluorine-based resin becomes a problem, which may cause problems such as failure to obtain the required mechanical properties or a decrease in electrical properties.

Therefore, a fluorine-containing resin composition is proposed, wherein the fluorine-based resin is 30% to 70% by mass, the inorganic filler is 70% to 30% by mass, the inorganic filler is a spherical inorganic filler, and the cumulative distribution on a volume basis shows that 10% of D10 is greater than 1.5 μm, and similarly D50 is 10 μm to 15 μm, and the specific surface area of the inorganic filler is 3.0 ^m2 /g or less (see Patent Document 1).

According to the resin composition, by using an inorganic filler having a specific particle size distribution such as D10 greater than 1.5 μm and D50 of 10 μm to 15 μm, the particles with small particle sizes are reduced and the particles with relatively large particle sizes are provided. Even if the amount of inorganic filler added is increased, the deterioration of the interaction with the fluorine-based resin can be suppressed, and the reduction of electrical properties or withstand voltage performance can be prevented. When a printed circuit board is obtained, it can have excellent dielectric properties and withstand voltage characteristics. [Prior art literature] [Patent literature]

[Patent Document 1] Specification of Chinese Patent No. 112574521

[Problems to be solved by the invention] With respect to a resin composition containing a fluorine-based resin and an inorganic filler, according to the invention of the aforementioned patent document 1, a larger amount of inorganic filler can be added, which is beneficial in that the functions accompanying the inorganic filler can be utilized to the maximum extent.

However, the inventors of the present invention have repeatedly conducted various experiments and found that: in terms of manufacturing a substrate material in which a fluorine-based resin is layered on a metal substrate, for example, it is important that the fluorine-based resin has sufficient adhesion to the metal substrate during circuit processing into a printed circuit board or in a heated or humidified environment. In order to ensure such adhesion and at the same time improve the filling capacity of the inorganic filler in the resin composition, there is room for further improvement.

Therefore, the inventors of the present invention have conducted intensive research on the above-mentioned problems and have found that by using an inorganic filler with a relatively large particle size and an inorganic filler with a relatively small particle size and adding an inorganic filler with a specified particle size distribution to a fluororesin at the same time, the adhesion of the fluororesin to a metal substrate, etc. can be improved, and the filling capacity of the inorganic filler in the resin composition can be improved, so that these can coexist, thereby completing the present invention.

Therefore, an object of the present invention is to provide a resin composition which can improve the filling property of an inorganic filler and ensure the adhesion of a fluorine-based resin on a substrate material such as a metal substrate by laminating the fluorine-based resin.

In addition, another object of the present invention is to provide a fluorine-based resin film obtained from such a resin composition and having an inorganic filler at a high filling rate, and to provide a fluorine-based resin-coated metal laminate in which the filler-highly filled fluorine-based resin film is laminated with excellent adhesion to a metal substrate. [Means for Solving the Problem]

That is, the gist of the present invention is as follows. (1) A resin composition comprising a resin component (A) containing a fluorine-based resin and an inorganic filler (B), wherein the resin composition is characterized in that: the mass ratio of (A) to the total of (A) and (B) is 20% to 50%, and the mass ratio of (B) to the total of (A) and (B) is 50% to 80%, and further, the mass ratio of the fluorine-based resin in (A) is 50% or more, the volume ratio of particles of 3 μm or less in (B) is 10% or more and less than 30%, the D50 indicating 50% of the cumulative distribution on a volume basis is 8 μm or more and 15 μm or less, and the D90 indicating 90% of the cumulative distribution on a volume basis is 30 μm or less. (2) The resin composition as described in (1), wherein the mass ratio of the fluorine-based resin in (A) is 70% or more, and the fluorine-based resin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. (3) The resin composition as described in (1), wherein (B) is spherical silica and is surface-treated with a single type of surface treatment agent. (4) The resin composition as described in (1), wherein the volume ratio of particles of 3 μm or less in (B) is 10% or more and less than 20%, the D50 representing 50% in the cumulative distribution on a volume basis is 8 μm or more and 10 μm or less, and the D100 representing 100% in the cumulative distribution on a volume basis is 30 μm or less. (5) A resin composition as described in (1), wherein in (B), the cumulative distribution on a volume basis indicates that 10% of D10 is less than 1.5 μm. (6) A fluororesin film comprising a resin composition as described in any one of (1) to (5). (7) A fluororesin-coated metal laminate comprising: a fluororesin film comprising a resin composition as described in any one of (1) to (5), and a metal foil. (8) A printed wiring board using the fluororesin-coated metal laminate as described in (7). [Effect of the invention]

According to the present invention, the adhesion of the fluorine-based resin to the metal substrate and the like can be improved, and the filling property of the inorganic filler in the resin composition can be improved. Therefore, while using a fluorine-based resin having electrical properties such as low dielectric properties and low dielectric loss, a substrate material with excellent reliability can be obtained, which is an extremely useful invention with high industrial utilization value.

The present invention is described in detail below. The resin composition of the present invention comprises a resin component (A) containing a fluorine-based resin and an inorganic filler (B), wherein the mass ratio of (A) to the total of (A) and (B) is 20% to 50%, and the mass ratio of (B) to the total of (A) and (B) is 50% to 80%, and the mass ratio of the fluorine-based resin in (A) is 50% or more, and the volume ratio of particles of 3 μm or less in (B) is 10% or more and less than 30%, and the D50 indicating 50% of the cumulative distribution on a volume basis is 8 μm or more and 15 μm or less, and the D90 indicating 90% of the cumulative distribution on a volume basis is 30 μm or less.

The ratio (mass ratio) of (A) to the total of (A) and (B) is preferably 25% to 40% by mass, and the ratio (mass) of (B) to the total of (A) and (B) is preferably 60% to 75% by mass. In this way, the resin composition of the present invention can be filled with a relatively large amount of the inorganic filler (B) relative to the resin component (A).

In the present invention, the resin component (A) includes a fluorine-based resin. The fluorine-based resin may be any resin containing fluorine (fluorine-containing resin), for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), chlorotrifluoroethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride (PVDF), and thermoplastic fluorocarbon resin (THV) composed of three monomers of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride.

Fluorine-based resins may include the above-listed resins and may be used alone or in combination of two or more. Among them, when the fluorine-based resin is used for substrate materials such as printed circuit boards, for example, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP) are preferred from the viewpoints of being suitable for heat-pressing when the resin layer is formed by coating on a metal substrate and having excellent heat resistance.

In addition, considering the use of preparing a slurry in which an inorganic filler and a fluorine-based resin are dispersed or coating the slurry on a metal substrate such as a metal foil, the fluorine-based resin is preferably used in a particle form (powder form). Examples of such particulate fluorine-based resins on the market include Fluon+ (a registered trademark of Fluon) manufactured by AGC, Algoflon PFA P series (a registered trademark of Algoflon) manufactured by Solvay, and Teflon PFA (a registered trademark of Teflon) manufactured by Mitsui Chemours Fluoroproducts Co., Ltd.

In addition, the resin component (A) may also contain resins other than fluorine-based resins. Such resins are not particularly limited and can be appropriately selected according to the purpose of the resin composition, for example: polyimide resins, liquid crystal polymers, cycloolefin polymers, cycloolefin copolymers, styrene-butadiene copolymers, styrene-ethylene/butylene-styrene copolymers, styrene-ethylene/propylene-styrene copolymers, etc. In the case where a resin other than fluorine-based resins is contained as the resin component (A), the proportion (mass ratio) of the fluorine-based resin in the resin component (A) may be 50% by mass or more, preferably 70% by mass or more, and more preferably 75% by mass or more.

In the inorganic filler (B) of the present invention, the proportion (volume proportion) of particles of 3 μm or less is 10 vol% or more and less than 30 vol%, preferably 10 vol% or more and less than 20 vol%. Particles of 3 μm or less correspond to particles of small particle size in the inorganic filler (B), and the presence of particles of D50 corresponding to particles of relatively large particle size described later play the role of improving the filling property of the inorganic filler when a resin layer of a substrate material or the like is formed from a resin composition. If the volume proportion of particles of 3 μm or less is less than 10 vol%, there is a risk that the effect of increasing the filling density of the filler when forming the resin layer may not be sufficiently obtained. On the other hand, if the volume ratio of particles smaller than 3 μm is 30 vol% or more, when forming a resin layer of a substrate material, the distance between fillers and adjacent parts will become too large. As a result, when stress is applied, stress relief in the resin layer does not work, and stress is concentrated on the filler interface, which reduces the adhesion between the filler and the resin, and there is a risk of peeling from the metal base material constituting the substrate material.

In addition, in the inorganic filler (B), the cumulative distribution on a volume basis indicates that 50% of the D50 is 8 μm or more and 15 μm or less, preferably 8 μm or more and 10 μm or less. As described above, the particles of D50 are equivalent to particles of relatively large particle size, and the presence of the large particle size ensures the distance between the fillers and alleviates the stress concentration at the filler interface. If D50 is less than 8 μm, it is difficult to ensure such a distance between the fillers, and the stress is concentrated on the filler interface, the close contact between the filler and the resin is reduced, and there is a risk of peeling from the metal substrate, etc. On the contrary, if D50 exceeds 15 μm, the space between the fillers becomes too much, and the uniformity of the filler properties in the resin layer cannot be guaranteed, or it is difficult to increase the filling density of the filler.

Furthermore, in the inorganic filler (B), the D90 representing 90% of the cumulative distribution on a volume basis is 30 μm or less, preferably 10 μm or more and 25 μm or less. By setting D90 to 30 μm or less, coarse particles are excluded, so that cracks caused by bending when forming substrate materials such as printed circuit boards are less likely to occur. From the same point of view, it is preferred that the D100 representing 100% of the cumulative distribution on a volume basis is 30 μm or less, and more preferably 15 μm or more and 25 μm or less. On the other hand, as described above, in the inorganic filler (B) of the present invention in which particles with relatively small particle sizes are controlled, the D10 representing 10% of the cumulative distribution on a volume basis is preferably less than 1.5 μm, and more preferably 0.5 μm or more and 1.5 μm or less. In the present invention, the particle size or particle size distribution of the inorganic filler (B) is determined based on a frequency distribution curve of the inorganic filler obtained by volume-based particle size distribution measurement using a laser diffraction-scattering method.

The specific surface area of the inorganic filler (B) can be 0.1 m ² /g to 5.0 m ² /g, preferably 0.5 m ^{2 /} g to 4.0 m ² /g, as measured by the Brunauer-Emmett-Teller (BET) method.

As the inorganic filler (B), any filler containing inorganic atoms may be used, and examples thereof include titanium oxide, talc, silicon dioxide, aluminum oxide, zirconium oxide, barium sulfate, calcium carbonate, aluminum hydroxide, magnesium hydroxide, potassium titanate, magnesium oxide, calcium oxide, clay, etc. Among them, silicon dioxide, titanium oxide, and talc are preferred, and silicon dioxide is more preferred. The inorganic filler (B) may contain one or more of these.

In addition, there is no particular limitation on the shape of the inorganic filler (B), and granular, spherical, scaly, needle-shaped, etc. can be used. Among them, for example, if the inorganic filler (B) is scaly or needle-shaped, the filler with anisotropy can be arranged in the resin layer of the substrate material. On the other hand, if the inorganic filler (B) is spherical, the surface area is small, and the viscosity increase when the resin composition is made can be suppressed. In the present invention, it is preferred to use a spherical filler such as spherical silica.

In addition, the inorganic filler (B) may be surface treated with a surface treatment agent for the purpose of improving affinity with the resin component (A). Examples of the surface treatment agent used in the surface treatment include various silane coupling agents, or hexamethyldisilazane or titanium ester coupling agents, aluminum ester coupling agents, etc. The surface treatment may be performed using one or more of these, but preferably, the surface treatment is performed using a single type of surface treatment agent.

The resin composition of the present invention can have a viscosity (25° C.) of, for example, 100 cps to 100,000 cps, preferably 500 cps to 5,000 cps, from the viewpoint of improving its handleability and facilitating the formation of a coating film of uniform thickness when applying (coating) to a metal substrate or the like when obtaining a substrate material such as a printed circuit board.

In addition, the resin composition of the present invention may contain components other than the resin component (A) or the inorganic filler (B) as needed. Examples of such arbitrary components include: surfactants, plasticizers, hardening accelerators, pigments, flame retardants, compatibilizers, crystallizers, etc. In addition, solvents may be added for the purpose of adjusting viscosity, etc. However, it is necessary to ensure that these arbitrary components do not affect the performance of the effects of the present invention. Ideally, in the solid component concentration of the resin composition of the present invention, the total mass ratio of the resin component (A) and the inorganic filler (B) can be 50% or more.

The resin composition of the present invention can be applied to a support material, and after the coating is cured, it can be peeled off from the support material to obtain a fluorine-based resin film, or it can be applied to a metal substrate including a metal foil and the like and the coating is cured to obtain a fluorine-based resin-coated metal laminate including a metal substrate and a resin layer. The fluorine-based resin-coated metal laminate can be a single-sided metal-coated laminate having a metal substrate only on one side of a resin layer including the resin composition of the present invention, or a double-sided metal-coated laminate having a metal substrate on both sides of the resin layer. In particular, a fluorine-based resin metal-coated laminate including a resin layer containing the resin composition of the present invention is preferably used as a substrate material for a printed circuit board, a circuit board, a flexible substrate, an antenna substrate, etc., which are intended to be used in a high-frequency region.

Specifically, the resin layer constituting the fluorine-based resin film or the fluorine-based resin-coated metal laminate is formed of the resin composition of the present invention, so that, for example, the dielectric loss tangent (Tanδ) at 60 GHz can be less than 0.005, and preferably less than 0.004. In order to improve the transmission loss of the substrate material, it is particularly important to control the dielectric loss tangent of the resin layer. By making the dielectric loss tangent within the above range, the effect of reducing the transmission loss is increased. In addition, the relative dielectric constant at 60 GHz can be less than 4, and preferably less than 3. Similarly, when a resin layer is used as a substrate material, it is important to ensure impedance matching. By making the relative dielectric constant within the above range, it is possible to prevent deterioration of dielectric loss and reduce the loss of electrical signals on the transmission path of high-frequency signals.

In addition, the coefficient of thermal expansion (CTE) of the resin layer (fluororesin layer) constituting the fluororesin film or the fluororesin-coated metal laminate may be in the range of 5×10 ^-6 /K to 40×10 ^-6 /K (5 ppm/K to 40 ppm/K), preferably in the range of 10×10 ^-6 /K to 35×10 ^-6 /K (10 ppm/K to 35 ppm/K). By having the coefficient of thermal expansion of the fluororesin film or the resin layer in the above range, dimensional stability or heat resistance as a substrate material can be ensured.

The thickness of the fluorine-based resin film or resin layer can be appropriately set according to its purpose or application, and is not limited. For example, it can be in the range of 5 μm to 200 μm, and preferably in the range of 45 μm to 150 μm.

In addition, there is no particular limitation on the metal substrate constituting the fluorine-based resin-coated metal laminate, and examples thereof include copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, and alloys thereof. These may be made of metal foil, or may be formed by metal deposition on a film, and metal foil is preferred, and copper foil made of copper or a copper alloy is more preferred.

The thickness of the metal substrate can be appropriately set according to the purpose of use of the fluorine-based resin-coated metal laminate, and there is no particular limitation. For example, it is preferably in the range of 5 μm to 3 mm, and more preferably in the range of 12 μm to 1 mm. In addition, even when a metal foil such as copper foil is used, the resin composition of the present invention can form a resin layer with excellent adhesion to the metal substrate, so there is no need to use a metal foil with a particularly large surface roughness. For example, since a low-roughness metal foil with a ten-point average roughness (Rzjis) of about 0.1 μm to 1.5 μm can be used, the decrease in high-frequency characteristics caused by the metal foil can be suppressed. Furthermore, the ten-point average roughness here is based on the roughness of Japanese Industrial Standard (JIS) B 0601-2001. [Implementation example]

The following examples are given to more specifically illustrate the features of the present invention. However, the scope of the present invention is not limited to the examples. Furthermore, in the following examples, unless otherwise specified, various measurements and evaluations are as follows.

[Particle size measurement of amorphous silicon dioxide] Using a laser diffraction particle size distribution measuring device (manufactured by Malvern, trade name: Mastersizer 3000), with water as the dispersion medium, the particle size was measured by the laser diffraction-scattering method under the condition of a particle refractive index of 1.54.

[Measurement of specific surface area] The specific surface area was measured by the BET method using Tristar II manufactured by Micromeritics.

[Measurement of surface roughness of copper foil] The surface roughness of copper foil was measured using an atomic force microscope (AFM) (manufactured by Bruker AXS, trade name: Dimension Icon Scanning Probe Microscopy (SPM)) and a probe (manufactured by Bruker AXS, trade name: TESPA (NCHV), tip curvature radius 10 nm, spring constant 42 N/m) in tapping mode on the surface of the copper foil in an area of 80 μm × 80 μm, and the ten-point average roughness (Rzjis) was calculated. The ten-point average roughness (Rzjis) is based on the roughness of JIS B0601-2001.

[Viscosity measurement] Using an E-type viscometer (manufactured by Brookfield, trade name: DV-II+Pro, rotor type: spindle rotor), the viscosity at 25°C was measured at a rotation speed of 100 rpm.

[Measurement of thermal expansion coefficient (CTE)] A fluorine-based resin film obtained from a double-sided copper-clad laminate cut into a size of 3 mm × 20 mm was placed in a thermal mechanical analyzer (Hitachi High-Technology (formerly Seiko Instruments), trade name: TMA/SS7100). At this time, the distance between the device fixtures (measurement effective length) was set to 15 mm. Next, a load of 5.0 g was applied while the temperature was raised from 30°C to 260°C at a constant rate of increase, and then the temperature was maintained for 10 minutes, and then cooled at a rate of 5°C/min, and the average thermal expansion coefficient (thermal expansion coefficient) from 200°C to 100°C was calculated.

[Measurement of dielectric properties] The relative dielectric constant (Dk) and dielectric loss tangent (Df) of the fluorine resin film obtained from the double-sided copper-clad laminate at 60 GHz were measured using a split cylindrical resonator (SCR resonator). The film used in the measurement was left for 24 hours at a temperature of 24°C to 26°C and a humidity of 45% to 55%.

[Peel strength measurement] The copper foil on one side of the double-sided copper-clad laminate was processed with circuits at intervals of 10 mm in the direction of the fluorine-based resin coating with a width of 1 mm, and then cut into pieces with a width of 8 cm × a length of 4 cm. At this time, the copper foil on the other side was not processed with circuits and the entire surface remained. Regarding the peeling strength, a Tensilon testing machine (manufactured by Toyo Seiki Seisaku-sho, trade name: Strograph VE-1D) was used to fix the entire surface of the cut test sample with the remaining copper foil to an aluminum plate with double-sided tape, and the copper foil after circuit processing was peeled off at a speed of 50 mm/min in a 180° direction. The median strength when 10 mm was peeled off from the fluorine resin layer was determined as the peeling strength.

[Void Evaluation] For the manufactured double-sided copper-clad laminate, a cross section polisher was used to make a precision polished section perpendicular to the double-sided copper-clad laminate. Five images of the fluorine-based resin layer containing inorganic fillers were randomly obtained at a magnification of 2000 times for the section using a scanning electron microscope (SEM). Next, the void part of the obtained image and the other parts were binarized to calculate the volume ratio of the voids in the fluorine-based resin layer containing inorganic fillers. Void ratio (vol.%) = X/Y (Here, X refers to the volume of the void part in the image, and Y refers to the volume of the fluorine resin layer containing inorganic filler in the image) In addition, the void ratio is the average value of the void ratio calculated based on the above formula for any five images (each image is about 300 μm×100 μm). At this time, the case where the void ratio is less than 3 vol% is set to ○, the case where the void ratio is 3 vol% or more and less than 5 vol% is set to △, and the case where the void ratio is 5 vol% or more is set to ×.

The compounds used in the synthesis examples and the dispersion composition preparation examples are shown below. <Silica filler> Silica fillers (1) to (8) shown in Table 1 below were used.

[Table 1] Silica Filler (1) Silica Filler (2) Silica Filler (3) Silica Filler (4) Silica Filler (5) Silica Filler (6) Silica Filler (7) Silica Filler (8) Specific surface area (m ² /g) 1.2 1.6 1.6 2.8 3.5 5.5 9.0 9.2 Surface treatment type Hexamethyldisilazane Surface treatment amount (mass%) 0.12 0.16 0.16 0.28 0.35 0.55 0.90 0.92 Particle size (μm) D10 3.27 1.45 1.94 1.38 0.50 0.45 0.38 0.85 D50 9.92 9.61 9.62 8.53 7.38 3.55 0.58 1.96 D90 16.99 16.79 16.85 16.34 15.76 14.84 1.00 3.79 D100 24.10 24.10 24.10 24.10 24.10 24.10 5.92 5.92 Volume ratio of particles smaller than 3 μm (%) 9.83 14.25 13.28 23.62 36.34 49.61 98.23 78.75

<Fluorine resin powder (1)> Fluon+ (Fluon is a registered trademark) EA-2000PW 10: Fluorine resin powder manufactured by AGC, average particle size: 2 μm to 3 μm, melting point: 300°C <Dispersant (1)> Ftergent 710FL: Non-ionic fluorine-containing dispersant manufactured by NEOS (dispersant component: 50% by weight, ethyl acetate: 50% by weight) <NMP> N-methyl-2-pyrrolidone <DMAc> N,N-dimethylacetamide <Xylene> <BTDA> 3,3',4,4'-Benzophenonetetracarboxylic dianhydride <DDA> C36 aliphatic diamine (Croda Japan) Co., Ltd., trade name: Priamine 1074, amine value: 210 mgKOH/g, mixture of dimer diamines with ring structure and chain structure, dimer component content: 95% by weight or more)

(Preparation of soluble polyimide varnish (1)) In a 500 mL four-necked flask equipped with a nitrogen inlet tube, a stirrer, a thermocouple, a Dean-Stark trap, and a cooling tube, 45.11 g of BTDA (0.139 mol), 75.08 g of DDA (0.141 mol), 168 g of NMP, and 112 g of xylene were placed and mixed at 40°C for 30 minutes to prepare a polyimide solution. The polyimide solution was heated to 190°C, heated and stirred for 4 hours, and the distilled water and xylene were removed from the system. Thereafter, the mixture was cooled to 100°C, 112 g of xylene was added and stirred, and the mixture was further cooled to 30°C to prepare a soluble polyimide varnish (1) (solid content: 31.0% by weight, weight average molecular weight: 75,700) that had been imidized.

(Example 1 for preparing a dispersed composition) In a container of T.K.HIVISMIX (model 2P-03) of Primix Co., Ltd. (formerly known as Tokushiki Kagaku Co., Ltd.), 70.4 g of fluororesin powder (1), 169.6 g of silica filler (1), 12 g of dispersant (1) (dispersant component 6 g), and 14.7 g of DMAc were added, and stirred at 20 rpm for 5 minutes at room temperature. Thereafter, the device was stopped, and the mixture was scraped off the stirring blades and the side wall of the container. The above stirring and scraping of the mixture from the stirring blades and the side wall of the container after the device was stopped were performed three times.

Next, in order to fine-tune the ratio of the fluororesin powder (1) to the silica filler (1) relative to the total amount, a small amount of DMAc was added to the kneaded product, and the mixture was stirred at 30 rpm for 5 minutes to check the state of the kneaded product. This operation was repeated until the kneaded product became a block without a powdery portion. In this study, when the total mass ratio of the fluororesin powder (1) and the silica filler (1) relative to the amount of DMAc added thereto was 85 mass % (i.e., [[fluororesin powder (1)] + [silica filler (1)]] / [[fluororesin powder (1)] + [silica filler (1)] + [DMAc]] = 85 mass %]), the mixture became a block, and no powdery portion was observed inside the block of the kneaded product. From the block state, the mixture was stirred at a speed of 30 rpm, and the mixture was stopped every 15 minutes to scrape the mixture from the stirring blades and the side wall of the container. This operation was performed 4 times in total, and the total stirring time was 60 minutes to obtain a dispersion composition (resin composition) 1-1. The dispersion composition 1-1 had no fluidity and the viscosity could not be measured, so it was judged to be "solid".

Thereafter, the dispersion composition 1-1 was gradually diluted and stirred with DMAc in such a manner that the total ratio of the fluorine-based resin powder (1) and the silica filler (1) to the amount after the addition of DMAc was 67.5 wt %, thereby obtaining a dispersion composition (resin composition) 1-2 having a viscosity (25° C.) of 940 cP (940 mPa·S) when measured at 100 rpm.

(Preparation Example 2 of Dispersed Composition to Preparation Example 8 of Dispersed Composition) Except that the type of silica filler is changed to silica filler (2) to silica filler (8), the same method as in Preparation Example 1 of Dispersed Composition is used to prepare dispersion compositions 2-1 to dispersion compositions 8-1 and dispersion compositions 2-2 to dispersion compositions 8-2. That is, except that silica filler (1) is changed to silica filler (2), dispersion composition 2-1 is obtained by the same operation as dispersion composition 1-1, and dispersion composition 2-2 is obtained by the same operation as dispersion composition 1-2. In addition, except that the silica filler (1) was replaced by the silica filler (3), the dispersion composition 3-1 was obtained by the same operation as the dispersion composition 1-1, and the dispersion composition 3-2 was obtained by the same operation as the dispersion composition 1-2. Similarly, the silica filler (1) was replaced by the silica filler (4) to the silica filler (8), and the dispersion compositions 4-1 to 8-1 and the dispersion compositions 4-2 to 8-2 were obtained respectively. In addition, since the viscosity of the dispersion compositions 2-1 to 8-1 could not be measured due to the lack of fluidity, they were judged to be "solid". In addition, the viscosity (25°C) of the dispersion compositions 2-2 to 8-2 when measured at 100 rpm is shown in the following Table 2.

(Example 9 for preparing a dispersed composition) In a container of T.K.HIVISMIX (model 2P-03) of Primix Co., Ltd. (formerly known as Tokushiki Kagaku Co., Ltd.), 82.3 g of fluorine-based resin powder (1), 157.5 g of silica filler (1), 12 g of dispersant (1) (dispersant component 6 g), and 14.7 g of DMAc were added, and stirred at 20 rpm for 5 minutes at room temperature. Thereafter, the device was stopped, and the mixture was scraped off the stirring blades and the side wall of the container. The above stirring and scraping of the mixture from the stirring blades and the side wall of the container after the device was stopped were performed three times.

Next, in order to fine-tune the ratio of the fluororesin powder (1) and the silica filler (1) relative to the total amount, a small amount of DMAc was added to the mixture, and the mixture was stirred at 30 rpm for 5 minutes to confirm the state of the mixture. This operation was repeated until the mixture became a block without a powdery part. In this study, when the total ratio of the fluororesin powder (1) and the silica filler (1) relative to the amount after adding DMAc to them was 85% by weight, it became a block, and no powdery part was observed inside the block of the mixture. From the state of becoming the block, stirring was performed at a speed of 30 rpm, and it was stopped every 15 minutes to scrape the mixture from the stirring blades and the side walls of the container. This operation was repeated 4 times for a total of 60 minutes of thickening to obtain a dispersion composition 9-1. The dispersion composition 9-1 was judged to be "solid" because its viscosity could not be measured due to lack of fluidity.

Thereafter, the dispersion composition 9-1 was gradually diluted and stirred with DMAc in such a manner that the total ratio of the fluorine-based resin powder (1) and the silica filler (1) to the amount after the addition of DMAc was 67.5 wt %, thereby obtaining a dispersion composition 9-2 having a viscosity (25° C.) of 1050 cP when measured at 100 rpm.

(Preparation Example 10 of Dispersed Composition to Preparation Example 12 of Dispersed Composition) Except that the type of silica filler is changed to silica filler (2) to silica filler (4), the same method as in Preparation Example 9 of Dispersed Composition is used to prepare dispersion compositions 10-1 to dispersion compositions 12-1 and dispersion compositions 10-2 to dispersion compositions 12-2. That is, except that silica filler (1) is changed to silica filler (2), dispersion composition 10-1 is obtained by the same operation as dispersion composition 9-1, and dispersion composition 10-2 is obtained by the same operation as dispersion composition 9-2. In addition, except that the silica filler (1) was replaced by the silica filler (3), the dispersion composition 11-1 was obtained by operating the same as the dispersion composition 9-1, and the dispersion composition 11-2 was obtained by operating the same as the dispersion composition 9-2. Similarly, the silica filler (1) was replaced by the silica filler (4), and the dispersion compositions 12-1 and 12-2 were obtained respectively. In addition, since the viscosity of the dispersion compositions 10-1 to 12-1 could not be measured due to lack of fluidity, they were judged to be "solid". In addition, the viscosity (25°C) of the dispersion compositions 10-2 to 12-2 when measured at 100 rpm is shown in Table 2.

(Example 13 of preparing dispersed composition) In a container of T.K.HIVISMIX (model 2P-03) of Primix Co., Ltd. (formerly known as Tokushiki Kagaku Co., Ltd.), add 76.7 g of fluororesin powder (1), 163.3 g of silica filler (2), 12 g of dispersant (1) (dispersant component 6 g), and 14.7 g of DMAc, and stir at 20 rpm for 5 minutes. Thereafter, stop the device and scrape the mixture from the stirring blade and the side wall of the container. The above stirring and scraping of the mixture from the stirring blade and the side wall of the container after stopping the device are performed three times.

Next, in order to fine-tune the ratio of the fluororesin powder (1) and the silica filler (2) relative to the total amount, a small amount of DMAc was added to the mixture, and the mixture was stirred at 30 rpm for 5 minutes to confirm the state of the mixture. This operation was repeated until the mixture became a block without a powdery part. In this study, when the total ratio of the fluororesin powder (1) and the silica filler (2) relative to the amount after adding DMAc to them was 85% by weight, it became a block, and no powdery part was observed inside the block of the mixture. From the state of becoming the block, the mixture was stirred at a speed of 30 rpm, and it was stopped every 15 minutes to scrape the mixture from the stirring blades and the side walls of the container. This operation was repeated 4 times for a total of 60 minutes of stirring to obtain a dispersion composition 13-1. The dispersion composition 13-1 was judged to be "solid" because its viscosity could not be measured due to lack of fluidity.

Subsequently, the dispersion composition 13-1 was gradually diluted and stirred with DMAc in such a manner that the total ratio of the fluorine-based resin powder (1) and the silica filler (2) was 67.5% by weight relative to the amount after the addition of DMAc, and then 14.1 g of the soluble polyimide varnish (1) was added, and further stirred to obtain a dispersion composition 13-2 having a viscosity (25° C.) of 1860 cP when measured at 100 rpm.

[Table 2] Dispersed composition 1-2 2-2 3-2 4-2 5-2 6-2 7-2 Viscosity (cP) 940 1020 980 1120 1220 1280 1350 Dispersed composition 8-2 9-2 10-2 11-2 12-2 13-2 Viscosity (cP) 1300 1050 1090 1020 1180 1860

<Example 1> After applying the dispersion composition 1-2 on a copper foil (electrolytic copper foil, thickness: 12 μm, ten-point average roughness (Rzjis) of the resin layer side: 0.6 μm), a drying treatment was performed in a hot air oven under an atmospheric environment at 80°C for 1 minute and at 120°C for 3 minutes. Next, the following nitrogen heat treatment is performed: using a hot air oven in a nitrogen environment (oxygen concentration of less than 0.1 volume %), the temperature is raised from 40°C to 240°C at 10°C/min, and from 240°C to 360°C at 5°C/min, and after being kept at 340°C for 5 minutes, it is cooled to 40°C, thereby obtaining a single-sided copper-clad laminate (fluororesin-clad metal laminate) 1 including a fluororesin layer containing the dispersed composition 1-2 on one side of the copper foil.

Two single-sided copper-clad laminates 1 obtained as described above were prepared, and the resin surfaces of the respective fluorine-based resin layers were overlapped and placed in a batch press, and then heated to 360°C under vacuum. After reaching 360°C, they were pressed at a pressure of 8 MPa for 5 minutes, thereby obtaining a double-sided copper-clad laminate 1 with a dielectric thickness of 100 μm, in which two fluorine-based resin layers were heat-pressed. For the obtained double-sided copper-clad laminate 1, the copper foil on one side was processed into a 1 mm wiring shape, and the peel strength was measured, and the result was 0.69 kN/m.

Next, the copper foil of the double-sided copper-clad laminate 1 was etched away using an aqueous solution of ferric chloride to prepare a fluorine-based resin film 1. The CTE of the fluorine-based resin film 1 was 24.5 ppm/K, the relative dielectric constant (Dk) was 2.9, and the dielectric loss tangent (Df) was 0.0010.

<Example 2 to Example 9 and Comparative Example 1 to Comparative Example 4> Except for changing the type of dispersant composition, the same method as Example 1 was used to prepare single-sided copper-clad laminates 2 to 13, double-sided copper-clad laminates 2 to 13, and fluorine-based resin films 2 to 13. The various evaluation results of the obtained materials are summarized in Tables 3 and 4.

[table 3] Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Embodiment 6 Embodiment 7 Dispersion composition applied on copper foil Dispersible composition 1-2 Dispersed composition 2-2 Dispersed composition 3-2 Dispersed composition 4-2 Dispersed composition 9-2 Dispersed composition 10-2 Dispersed composition 11-2 Single-sided copper-clad laminate Single-sided copper-clad laminate 1 Single-sided copper-clad laminate 2 Single-sided copper-clad laminate 3 Single-sided copper-clad laminate 4 Single-sided copper-clad laminate 5 Single-sided copper-clad laminate 6 Single-sided copper-clad laminate 7 Double-sided copper laminate Double-sided copper laminate 1 Double-sided copper laminate 2 Double-sided copper laminate 3 Double-sided copper laminate 4 Double-sided copper laminate 5 Double-sided copper laminate 6 Double-sided copper laminate 7 Fluorine resin film Fluorine resin film 1 Fluorine resin film 2 Fluorine resin film 3 Fluorine resin film 4 Fluorine resin film 5 Fluorine resin film 6 Fluorine resin film 7 Peeling strength (kN/m) 0.69 0.67 0.68 0.55 0.77 0.74 0.76 CTE (ppm/K) 24.5 27.5 28.1 34.1 29.8 33.4 34.6 Dk 2.9 2.9 2.9 2.9 2.9 2.9 2.9 Df 0.0010 0.0010 0.0010 0.0011 0.0010 0.0010 0.0010 Gaps in the insulation layer △ ○ △ ○ △ ○ ○

[Table 4] Embodiment 8 Embodiment 9 Comparison Example 1 Comparison Example 2 Comparison Example 3 Comparison Example 4 Dispersion composition applied on copper foil Dispersed composition 12-2 Dispersed composition 13-2 Dispersed composition 5-2 Dispersed composition 6-2 Dispersed composition 7-2 Dispersed composition 8-2 Single-sided copper-clad laminate Single-sided copper-clad laminate 8 Single-sided copper-clad laminate 9 Single-sided copper-clad laminate 10 Single-sided copper-clad laminate 11 Single-sided copper-clad laminate 12 Single-sided copper-clad laminate 13 Double-sided copper laminate Double-sided copper laminate 8 Double-sided copper laminate 9 Double-sided copper laminate 10 Double-sided copper laminate 11 Double-sided copper laminate 12 Double-sided copper laminate 13 Fluorine resin film Fluorine resin film 8 Fluorine resin film 9 Fluorine resin film 10 Fluorine resin film 11 Fluorine resin film 12 Fluorine resin film 13 Peeling strength (kN/m) 0.61 0.61 0.44 0.35 0.13 0.21 CTE (ppm/K) 38.8 29.4 32.2 22.7 16.6 17.6 Dk 2.9 2.9 2.9 2.9 2.9 2.9 Df 0.0011 0.0010 0.0012 0.0012 0.0014 0.0014 Gaps in the insulation layer ○ ○ ○ ○ × ×

From the above results, it can be seen that the peeling strength of the double-sided copper-clad laminates of Comparative Examples 1 to 4 is generally about 20% to 60% compared to that of the examples. In contrast, in Examples 1 to 9, materials that fully exhibit peeling strength and have excellent relative dielectric constant (Dk) and dielectric loss tangent (Df) in the measurement of the high-frequency region can be obtained. Therefore, according to the present invention, a fluorine-based resin having electrical properties such as low dielectric properties and low dielectric loss can be used to obtain a substrate material with excellent reliability.

without

without

Claims (8)

A resin composition having a resin component (A) containing a fluorine-based resin and an inorganic filler (B), wherein the resin composition is characterized in that: The mass ratio of (A) to the total of (A) and (B) is 20% to 50%, and the mass ratio of (B) to the total of (A) and (B) is 50% to 80%, and the mass ratio of the fluorine-based resin in (A) is 50% or more, The volume ratio of particles of 3 μm or less in (B) is 10% or more and less than 30%, the D50 indicating 50% of the cumulative distribution on a volume basis is 8 μm or more and 15 μm or less, and the D90 indicating 90% of the cumulative distribution on a volume basis is 30 μm or less. The resin composition according to claim 1, wherein the mass ratio of the fluorine-based resin in (A) is 70% or more, and the fluorine-based resin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. The resin composition according to claim 1, wherein (B) is spherical silica and is surface-treated with a single type of surface treatment agent. The resin composition as described in claim 1, wherein in (B), the volume ratio of particles of 3 μm or less is 10% or more and less than 20%, D50 representing 50% of the cumulative distribution on a volume basis is 8 μm or more and 10 μm or less, and D100 representing 100% of the cumulative distribution on a volume basis is 30 μm or less. The resin composition according to claim 1, wherein in (B), the cumulative distribution on a volume basis indicates that 10% of D10 is less than 1.5 μm. A fluorine-based resin film comprises the resin composition as described in any one of claims 1 to 5. A fluororesin-coated metal laminate comprises: a fluororesin film containing the resin composition as described in any one of claims 1 to 5, and a metal foil. A printed wiring board using the fluorine-based resin-coated metal laminate as described in claim 7.